1) Always read and follow the test kit instructions.2) Water samples should be taken ≥18” below water surface and away from the return line. 3) Make sure sample size is correct. Fill test cell so that the low point rests on fill mark.4) Match your colors by holding the comparator up to northern light.5) Swirl . . . swirl . . . swirl: Reagents must be thoroughly mixed in the water sample.6) When getting any liquid reagent from a bottle, hold the dropper bottle vertically (straight up and down) to get an accurate drop size.7) Prepare for the next test by flushing sample cells with tap water to avoid any residue from contaminating the next test.